<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>取消请求</title>
</head>
<style>
    #result {
        width: 200px;
        height: 100px;
        border: solid 1px #903;
    }
</style>

<body>
    <button>点击发送请求</button>
    <button>点击取消请求</button>
    <div id="result"></div>
    <script>
        const btns = document.querySelectorAll('button');
        const result = document.getElementById('result');
        let xhr = null;
        btns[0].onclick = function() {
                xhr = new XMLHttpRequest();
                xhr.open('GET', 'http://127.0.0.1:8000/delay');
                xhr.send();
            }
            // abort  用来取消请求
        btns[1].onclick = function() {
            xhr.abort()
        }
    </script>
</body>

</html>